Circulation control for furnaces



May 4, 1937;

M. DE LIN \CIRCULATION CONTROL FOR FURNACES- Filed Oct. 7, 1935 2Sheets-Sheet 1 R \fix mni'or Mawfin mun 325-; W

3 .Afromg May 4, 1937. M. or; LIN I 2,079,157 CIRCULATION CONTROL FOR-FURNCES I Filed Oct. 7, 1935 2 Sheets-Sheet 2 iflafhn 136.1

- 'A'Womag 2o operate continuously at all times when the heat 45installation by a less experienced operator.-

Patented May 4, 1937 CIRCULATION QONTBOL FOB FURNACES Martin De Lin,Holland, Mich, assignor, to Holland Furnace Company, Holland, Mich,

a corporation of Michigan Application October 7, 1935, Serial No. 43,824

' z Claims. (01. 231-2) This invention relates to improvements incirpointed out in the claims, reference being had to culating systemsand controls for furnaces. The the accompanying drawings, in which,invention relates more specifically to the mecha- Fig. 1 is adiagrammatic elevation of a heat nism and system for circulating air ina warm ing system embodying this invention. 5 air heating systemalthough it may be adapted to Figure 2 is an enlarged sectionalelevation of a the circulation of other heating mediums such as fan withthe output control mechanism of this hot water. 7 invention appliedthereto taken on the line 2-2 The warm air heating system embodying thisof Fig. 3. invention includes a furnace, means for convey- Fig. 3 is asectional elevation of the fan and ing heated air from the furnace tothe room to be capacity control device taken on the line 3-3 of heatedand for returning air from the room to Fig. 2.

the furnace with a fan to induce air circulation. Fig. 4 is a plan viewof the control motor, and The fan has means for varying its delivery ca-Fig. 5 is an elevation of the same. pacity nd the system includesthermostatic con- Like numbers refer to like parts in all of the trol mns for stopping and starting operation of figures.

the fa with relation to the heat of the furnace i represents aconventional warm air furnace body and for varying the delivery capacityof the through the jacket of which air circulates to be fan relative tothe heat in the room. heated and 2 is a warm air conduit leading from Byuse of this invention the fan is caused to the furnace jacket to a room3 to be heated. A return air passage 4 is provided in the floor of theroom 3 through which air may circulate from mined point, the fan beingstopped and inoperathe room back tothe vicinity of the furnace and tivewhen the furnace heat is below said point. a fan 5. is provided toforcibly circulate the air Operation of the fan continuously at uniformthrough the jacket of the furnace into the I speed during the time whenthe furnace is sufliroom I.

ciently warm to give ofl heat to an appreciable The fan is of thecentrifugal type having a extent and controlling the amount of aircircasing 8 and a rotor of the so-called squirrel culated with relationto the heat of a room by case" type. The fan. shown has a double rotormeans of the variabledelivery capacity control provided W thfi ce di 3having a hub 9 of the fan has several advantages. A constant which isfixed to a shaft ll mounted in bearin peed motor may be used to drivethe fan which I! and driven by an electric motor I3.

is considerably cheaper and more simple than a The rotor blades 'Iextend in opposite directions variable speed motor or if the fan were tobe from the disk 8 and have their respective ends driven at varyingspeeds by a constant speed mofixed to rings l Which complete the W torvariable speed transmission devices would be struction. The casing t hasair inlet openings required which are eliminated by the present in- Iisurrounding the shaft If and of substantially UNITED STAT within, thefurnace jacket is above a predetervention. Furthermore, the output ofthe fan the same diameter as the inner diameter of the maybe moreaccurately controlled while running rotor within the blades 1 and anoutlet or deat a constant speed by the use of the -capacity liveryopening it and in its rotation air is thrown 40 control device than byvarying the speed offan outwardly from the rotor blades I by centrifugalrotation and also it is possible to have the most effective rotationspeed accurately determined by engineers at the factory and theoutput ofthe fan varied by the capacity control device at the.

replaced by air entering through the inlet openings ii.

The fan motor II is actuated by an electric circuit'carried by theconductors il in which is The invention also embodies a specific meansall d th r tatic limit switch Ill sub-. for controllin the de y capacityh fanjected to the heat within the jacket of the furwhich operates mosteffectively and quietly and nace i and adjusted to break the circuit inthe obviates Whis lin noises which are the objectionelectric conductorswhen the temperature in said able result of some other" types of fan'capacity jacket falls below a predetermined degree, for example, F.v andto close the circuit when The invention provides various new and usefulthe heat in the jacket is above that degree. Thus features ofconstruction and arrangementhereat all times when the .heat within thefurnace inafter more fully described and particularly jacket issufliciently high to have any appre force passing out through theopening I and is ciable effect on heating the room the fan rotor iscaused to continuously rotate.

The delivery capacity of the fan is varied by means of the sliding disks20. Because of the fact that the fan shown in the drawings is of doublestyle, that is, extending both sides from the center disk 8. a disk 20is provided on each side of the disk 8 and each disk controls thedelivery of its respective part of the fan rotor. The invention would beas fully embodied in a single style rotor having one control disk only.

The disks 20 are provided with hubs 2| freely mounted upon the shaft ifor both rotating and sliding movement. The disks 20 are ofsubstantially the same diameter as the inner diameter of .the rotor andmay be slightly conical as shown and their edges are preferably curvedinwardly which is in a direction away from the flow of air-entering therotor.

The disks may be slid longitudinally of the shaft from the positionsadjacent the central disk 8 as shown in full lines in Fig. 3 to extremeopposite positions adjacent the inlets l5 of the fan housing and serveto control the effective area of the rotor blades 1. When the disks arein their innermost positions the rotor is fully effective and deliversits maximum capacity of air. Movement of the disks-outwardly preventsthe flow of incoming airagainst the blades in varying degrees frommaximum to zero depending upon the extent to which the disks are moved.In other words, the disks serve as an effective guide for the incomingair against the rotor blades 1 and determine, by their positions, thelengths of the blades which will eifectively operate to circulate theair and thereby control the delivery capacity of the fan.

The disks 20 are non-rotative for the purpose of effecting automaticadjustment thereof during operation of the fan and inasmuch as theirhubs 2| are freely rotative on the shaft II the disks may be held fromrotation by a slight impedance such as cables 22 connected thereto andif desired weights 23 may also be attached to the disks near theirperiphery which also tend to prevent rotation thereof.

The incoming air current induced by expelling air from the periphery ofthe rotor by reason of centrifugal force is suflicient to normally movethe disks 20 to their innermost positions adjacent .the rotor disk 8 andthe cables 22 serve to move the disks outwardly to reduce the deliverycapacity of the fan. The cables 22, one attached to each disk 20, extendoutwardly through the open ends of the rotor and through the inletpassages I5 of the fan housing and thence pass over pulleys 23 and arerespectively connected to the cranks 24 of the control motor 25. Themeans of attachment of the cables 22 consist of links 23 pivotallyattached at 21 to the cranks 24 and adjustable radially'of the axis ofsaid cranks and adjustable connections 28 by means of which thecables 22are connected to andadjustable longitudinally of the links 26;

The control motor is a device commonly known in the art as affurnacedamper control motor" and it is so constructed that when it is actuatedby an electric current its shaft 23 will rotate one-half revolution andstop. The current to operate the control motor 25 is carried by electricconductors 30, 3| and 32 and these conductors are in circuit with a roomthermostatic switch 33 located in the room 3 to be heated and thecurrent to the control motor is' controlled by said thermostatic switch.3 50 tha the motor shaft 29 is 'rotated to one position when the roomtemperature is below a predetermined degree and is rotated. 180therefrom when the room temperature is above' said predetermined degree.

Rotation of the motor shaft 29 actuates the control disks20 through thecranks 24 attached to said shaft and the cables 22 adjustably connectedthegeto-sirthat the disks are free to move inwardly for greater fancapacity when the motor is rotated to ,position for cool roomtemperature and are moved outwardly for decreased i'an capacity when themotor is moved to position for warm room temperature. The adjustableconnections of the cables 22 to the cranks 24 permit the positions ofthe control disks 20 to be adjusted so that they will be moved. byactuation of the control motor 25, from extreme inner position toextreme outer position and vice versa or from any intermediate positionsthereby making it possible to cause the fan to deliver the maximum aircapacity into the air circulating system when the room temperature iscool and to run substantially idle with no air delivery when the roomtemperature is warm or to deliver 7 Operation 'By means of thisinvention it will be seen that the air circulation is entirelyautomatically controlled after the device'is adjusted to meet theexisting conditions. When the heat within the furnacejacket is below apredetermined degree, such as during warm weather when there is no firein the furnace or during mild weather when the furnace fire is low orfor other reasons, the limit switch l8 breaks the circuit in theconductor ll of the fan motor I3 and the fan does not operate. At alltimes when the heat in the furnace jacket is above a predetermineddegree and sumciently warm to appreciably heat the room the limit switchi3 closes the electrical circuit to the fan motor and the fancontinuously operates at a uniform speed which is most effective forproper operation.

During operation of the fan its delivery capacity is automaticallycontrolled with relation to the temperature in the room 3 and therequirement for heated air to be delivered thereto. If the roomtemperature is cool the room thermostat 33 closes an electric circuitthrough the conductors 30, 3| and 32 to operate the control motor 25 toa position which permits the control disks 2!! to move to increase thedelivery capacity of the fan. When the room temperature is warm thethermostat 33 dire'cts an electric current to operate the control motor25 to a position to move the control disks 2!! outwardly to reduce thedelivery capacity of the fan.-

The continuously rotating fan rotor makes it possible to circulate airthrough the furnace jacket and heating system at 'all times so that whenthe room is warm a reduced flow of air may be had with the result ofpreventing overheating of the furnace body and maintaining a warm.temperature in the room.

It is conceived that the invention may be modifled to circulate otherheating mediums than air.

v For example, in a hot water'heating system a water circulator havingmeans for varying its delivery capacity may be substituted for the fanand its delivery capacity controlled and this water circulator and'thecapacity control may be actuated and controlled in the same manner asherein I described for the fan. It is also conceived that other types offans or air circulating devices may be used in substitution for thecentrifugal anv herein disclosed and that other specific means forcontrolling the delivery capacity may be substituted either in thecentrifugal type of fan or in other types of fan all within the spiritof this 15 invention.

The invention is defined inthe appended claims and is tov be consideredcomprehensivepi all formsoi structure coming within their scope,

I claim:

1. A heating circulating system comprising, a

heater, a circulating system for conducting a heating medium from saidheater to a space to be heated, means for inducing circulation of saidheating medium in said circulating system, means for automaticallycausing operation or cessation of said circulation inducing means whensaid heater is above or below, respectively, a predetermined temperatureand means for automatically varying the delivery capacity of saidcirculation inducing means responsive to temperature changes in thespace to be heated.

2. A heating circulating system comprising, a

warm air heating furnace, means to conduct heated air from said furnaceto a space to be heated, a fan to circulate air from said furnace tosaid space. automatic means for causing continuous and constant speedoperation of saidian at all times when the heatfof said furnace is abovea predetermined degree and cessation of operation below saidpredetermined degree.

ation of said fan and electric means controlled by the temperature insaid space to actuated said means for varying the delivery capacity.

- MARTIN DE LIN.

means for varying the deliverycapacity of said fan, said means beingvariable during the. oper-

